This invention relates generally to step systems, and more particularly to modular step systems for swimming pools and methods for manufacturing the same.
Prefabricated stair modules which are carried to the site at which swimming pools are in the process of installation are known. Stair modules formed of acrylic/fiberglass laminates or vinyl covered metal are relatively strong and will support a person's weight without much flexure. However, such stair modules may delaminate, splinter, corrode or puncture. Unitary stair modules comprising shells formed of suitable plastic compositions that can withstand temperature related expansion and contraction are also known. However, such materials are generally relatively flexible so that their steps may yield under a person's weight, giving that person an insecure feeling.
Attempts have been made to reinforce the steps of such prefabricated plastic shell stair modules to make them more rigid. For example, the treads of the steps have been supported by stacks of concrete blocks. However, this requires building the support from the ground up and, therefore, requires shimming to insure proper levelling. U.S. Pat. No. 4,589,237 discloses the use of support posts having bearing plates or pads connected to their upper ends which are placed against the underside of a step tread to support the step from beneath. U.S. Pat. No. 4,873,802 discloses adhesively bonding a narrow longitudinal stiffening member to the underside of a stair tread, and using vertical support posts that engage the stiffening member to support the step.
Although such prior art stair modules and support systems are relatively easy to install and ship to the pool installation site, they have definite disadvantages. For example, the adhesive bonding of the stiffening member to the underside of the step is labor intensive, and therefore is expensive and time consuming, and the stiffening member may separate from the stair tread. The vertical support posts do not provide sufficient support and the stiffening member is not sufficiently wide to adequately eliminate the flexing of the stair tread.